The present invention relates to a door lever assembly that provides a failsafe mechanism for locking a door latch assembly. More specifically, the present invention relates to a door lever rotatably connected to a cam propelled slider for operating a door latch, with an electrically operated blocking arm selectively controlling movement of the slider.
Conventional door levers typically consist of a trim housing designed to accommodate a key cylinder lock positioned above a rotatable lever handle. The lever handle is ultimately connected to a door latch mechanism through a series of fixed or movable linkages that drive engagement or disengagement of one or more door latches. For example, the lever handle can be pinned to a shaft that extends through the trim housing to engage an eccentrically shaped cam. Turning the lever causes rotation of both the shaft and the cam, with the rotating cam upwardly impelling a slider having a connected lift arm. This upward movement of the lift arm in turn causes movement of vertical rods that retract the door latches.
In such a conventional door lever assembly, the door latch is locked by interrupting the linkage between the lift arm and the vertical rods. Rotation of the key cylinder swings a blocking slide (often called a "trim lock tumbler") into a position that prevents movement of the lift arm. This effectively prevents any movement of the attached slider, cam, shaft, and lever, as well as the vertical rods and connected door latches.
However, as will be appreciated by those skilled in the art, such key operated lock systems are not well suited to remote lock/unlock control. Further, in an emergency situation, use of a keyed lock device could slow or prevent emergency exit. What is needed is a door lever assembly that can be remotely locked or unlocked. Such a device should in addition have a failsafe feature that ensures the door lever assembly is unlocked if the remote locking mechanism is damaged. Finally, such a door lever assembly should further use conventional door lever assembly components as much as possible to reduce costs and simplify repair or replacement of components.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set for above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.